Direct Torque Control of a Permanent Magnet synchronous Motor

This work presents an improved variant of the Direct Torque Control (DTC) for a Permanent Magnet Synchronous Motor (PMSM). The improved DTC use a higher number of voltage space vectors by introducing a kind of Space Vector Modulation technique. The higher number of space vectors are tabulated in more precise switch tables which also take the emf induced in the stator windings into account. The emf voltage significantly affect the motor behavior from a given space vector. It is discussed how the switch tables are constructed. Experiments from the classical and improved DTC are compared and show that the torque, flux linkage and stator current ripples are significantly decreased with the improved DTC.